Design of a Continuous Wave Ultrasound Technique to Measure Both the Phase Velocity and Attenuation in Solids

Abstract

We developed a simple and versatile non-destructive testing method to simultaneously measure the phase velocity and attenuation of ultrasound wave propagation through solid medium. In this technique, a continuous ultrasound excitation emitting from the high-quality lithium niobate transducer passes through the solid medium and the transmitted signal is received by another identical LiNbO₃ crystal. To check the reliability of this method, the velocity and attenuation of both longitudinal and shear ultrasound waves have been measured at room temperature in aluminium and copper correspondingly which are consistent with previous research. Moreover, the versatility of this technique has been shown from the phase velocity measurement of the longitudinal excitation as a function of temperature which depicts interesting anomalies across the Verwey transition in Fe₃O₄ and critical temperature of ferromagnetic ordering in SrRuO₃, respectively.